Exercise 3
Alexandra Anderson
2023-09-20
Please Don’t Be Tired of This Data Yet (A Gila Monster Story)
I was lucky enough to already be using morphological data for my thesis project, so I decided to use the data I already had to kill 2 birds with one stone since I will be using some of these visualizations for my own project.
A T-Test
Here is my example of doing a T-test table and ggplot visualization for this exercise. Through my analysis you will see these same 9-10 morphological measurements that I collected for my thesis.
| Female1 | Male1 | P-value2 | |
|---|---|---|---|
| SVL (mm) | 265.2 (51.2) | 239.5 (65.1) | <0.001 |
| Tail Length (mm) | 124.0 (25.1) | 111.9 (34.1) | 0.004 |
| Trunk | 153.0 (34.5) | 135.3 (40.4) | <0.001 |
| Tail Diameter (mm) | 21.6 (6.2) | 20.0 (7.2) | 0.11 |
| Insert to Elbow Length (mm) | 16.8 (3.1) | 16.0 (4.5) | 0.29 |
| Elbow to Wrist Length (mm) | 21.6 (4.1) | 20.7 (5.8) | 0.45 |
| Wrist to 3rd Digit Length (mm) | 28.1 (4.8) | 26.6 (6.9) | 0.21 |
| Head Length (mm) | 45.1 (7.0) | 42.6 (10.1) | 0.14 |
| Head Width (mm) | 40.6 (7.7) | 38.6 (11.4) | 0.65 |
| Ear to Rostral Length (mm) | 50.5 (8.0) | 47.7 (12.0) | 0.35 |
| 1 Mean (SD) | |||
| 2 Wilcoxon rank sum test | |||
Here is a bar graph to act as a visualization for my T-test.
An ANOVA Analysis
Here is my ANOVA analysis for my data. For this section I chose to keep beaded lizard (Heloderma horridum) data in to allow for a between species comparison. As you can see, there is a large sample size difference between both the species and sexes.
| H. horridum | H. suspectum | P-value | |
|---|---|---|---|
| Sex | 0.018 | ||
| Â Â Â Â Female | 25 | 138 | |
| Â Â Â Â Male | 20 | 232 | |
| SVL | 310.7 (59.8) | 248.5 (61.5) | <0.001 |
| Tail Length | 223.1 (61.1) | 113.9 (35.4) | <0.001 |
| Trunk | 170.7 (36.1) | 142.3 (38.7) | <0.001 |
| Tail Diameter | 25.3 (6.4) | 20.6 (7.0) | <0.001 |
| Insert to Elbow Length | 22.3 (5.1) | 16.4 (4.1) | <0.001 |
| Elbow to Wrist Length | 28.9 (6.5) | 21.1 (5.2) | <0.001 |
| Wrist to 3rd Digit Length | 36.1 (6.8) | 27.3 (6.2) | <0.001 |
| Head Length | 52.3 (9.9) | 43.7 (9.1) | <0.001 |
| Head Width | 47.2 (11.4) | 39.4 (10.1) | <0.001 |
| Ear to Rostral Length | 58.4 (9.8) | 48.8 (10.6) | <0.001 |
Here is a visualization of one of the morphological measurements compared between species.
An ANCOVA Table
Here is an ANCOVA analysis done between sexes, including 9 of my morphological measurements after accounting for SVL. This is one of the types of analysis I will be using in my thesis.
| Characteristic | Female, N = 133 | Male, N = 225 | Adjusted Difference | 95% CI1 | p-value |
|---|---|---|---|---|---|
| Tail Length | 124.0(25.1) | 111.9(34.1) | -0.48 | -2.6, 1.6 | 0.7 |
| Trunk | 153.0(34.5) | 135.3(40.4) | 1.8 | -0.20, 3.9 | 0.077 |
| Tail Diameter | 21.6(6.2) | 20.0(7.2) | -0.90 | -1.7, -0.11 | 0.025 |
| Insert to Elbow Length | 16.8(3.1) | 16.0(4.5) | -0.70 | -1.2, -0.24 | 0.003 |
| Elbow to Wrist Length | 21.6(4.1) | 20.7(5.8) | -1.1 | -1.6, -0.53 | <0.001 |
| Wrist to 3rd Digit Length | 28.1(4.8) | 26.6(6.9) | -0.99 | -1.5, -0.51 | <0.001 |
| Head Length | 45.1(7.0) | 42.6(10.1) | -1.2 | -1.8, -0.59 | <0.001 |
| Head Width | 40.6(7.7) | 38.6(11.4) | -2.1 | -2.8, -1.3 | <0.001 |
| Ear to Rostral Length | 50.5(8.0) | 47.7(12.0) | -1.6 | -2.2, -1.1 | <0.001 |
| 1 CI = Confidence Interval | |||||
The ANCOVA visualization focusing on trunk size.
